I've been reading a lot here about how difficult and uncomfortable it is to focus any of the contax G lenses, and it has something to do with the adapter. So I just want to know why it's difficult, what about it makes it so difficult, and which adapters seem to be less troublesome.
Since the G lenses were made for the AF cameras Contax G1/G2 they dont have a focusing ring. Focusing was done through a screw mechanism found at the bottom of the lens mount. Hence, the adapter will have to use that screw and be equipped with a (quite primitive) focusing ring. Due to gearing it's not very smooth. And it varies too which can be pretty annoying. Perhaps it could be better implemented (more advanced gearing?) than current adapters.
Some adapters do have a larger ring than the cheapest, but I have yet to read that they're significantly better. They're never smooth and dont come close to a real focusing ring.
It's the superb quality of that glass that makes them so attractive anyway. And some of them can still be found pretty cheap (28/35/45/90).
I have one of the "Cheap" ones from e-bay, however I have very little complaint about it. Is it worse than a built in focus ring- yes.... do I mind it- no.
I have a cheap 'Nipon' branded ring. Just a shameless copy of the Kipon. It works OK with my Sonnar-G 90.
One thing I found is that when the adapter+lens is out of the camera, turning the focusing ring is a PITA, very stiff or even stuck; but once is mounted on the NEX it works reasonably well.
Even so, I'm thinking of replacing my Sonnar-G 90 with a C/Y Sonnar 85/2.8. The focus ring isn't the only ergonomic issue with G lenses. You haven't a focus scale on the lens; pre focus isn't possible. Also, the G mount isn't compatible with other Mirrorless systems, ( as the Ricoh GXR M mount A12).
